U.S. Pat. No. 2,935,213 discloses a weighing scale using strain gage networks carried in certain load cells disposed in the tines of a fork type lift vehicle. A bar disposed in the tines with a central raised portion permits deflection in a vertical plane and four load cell assemblies are provided for the bar.
U.S. Pat. No. 3,059,710 discloses a fork lift weighing apparatus employing electrical strain response means for weighing a load with a reasonable degree of accuracy regardless of where the load is placed on the fork tines.
U.S. Pat. No. 3,063,576 discloses the use of two load cells each having a single tension gauge and two load cells having a single compression gauge connected where each cell is one of the four legs of a Wheatstone bridge so that the summation of the responses from the four cells indicates the correct total weight of a given load.
U.S. Pat. No. 3,196,966 discloses load measuring devices on a fork lift truck which has spaced front and back plates with the front plate carrying the forks and the back plates secured to a mounting plate or mounting straps on a truck. Relative vertical and horizontal movement of the front and back plates is limited to avoid damage to the flexure strips and to the load cell.
U.S. Pat. No. 3,910,363 discloses a weighing device for use with a fork lift truck having a stationary plate and a moveable plate and at least one load cell interposed between the moveable and stationary plates.
U.S. Pat. No. 4,323,132 discloses a mounting adapter which provides a quick attachment for mounting or removing an electro-mechanical scale with respect to the lift frame of a fork lift truck.
U.S. Pat. No. 4,420,053 discloses a weighing apparatus for fork lifts comprising a weight bridge supported at each end by load cells, the weight bridge and load cells are built into the fork.
U.S. Pat. No. 4,421,186 discloses a fork lift scale which consists of horizontally disposed load sensors connecting a crossbar frame to the crossbars of a fork lift truck.
U.S. Pat. No. 4,638,876 discloses a weighing apparatus for weighing eccentric loads for use with a forklift which has a weighing plate, three weight measuring systems or weighing cells engage the weighing plate.
U.S. Pat. No. 4,666,004 discloses a pallet truck with a fork member movable in an up-and-down manner which is provided with a plurality of load cells on the tines of the fork member.
U.S. Pat. No. 4,714,122 discloses pressure load cells with "an upwardly extending sensing element 56 which protrudes from the main body of the load cell . . . . Each sensor 56 is biased upwardly relative to the main body of the load cell and is forced into the main body of the load cell by the downward pressure on the sensing element. The greater the weight or pressure on the sensing element, the greater the movement of the sensing element into the body of the load cell." Also disclosed, a limit switch is operatively connected to the transducer so that the transducer is energized at a point when a full container is supported by the lifting means and when an empty container is supported by the lifting means for the purpose of determining the weight of the refuse in the container.
U.S. Pat. No. 4,771,837 discloses a weighing system on a refuse truck which has a hydraulically actuated lifting means and a fluid pressure transducer which is operatively connected to the hydraulically actuated lifting means for sensing the weight of a refuse container when the container is lifted and lowered by the lifting means.
U.S. 4,854,406 discloses the weighing systems of U.S. Pat. No. 4,714,122 and U.S. Pat. No. 4,771,837 with emphasis on the electrical control system.
U.S. Pat. No. 4,899,840 discloses a weighing apparatus for a vehicle having tines in which a ramp is mounted on each tine in front of and in spaced relation to a weighing load bearing plate.
U.S. Pat. No. 5,245,137 discloses a method for determining a weight of material being emptied from a container.